Factory frame metal -- ALS450, cromoly, etc

[Speeddog]

Yes, that's it.  All types of alloy steels weigh about the same, for all practical purposes.  With stronger material you can use thinner wall tubing for the same strength.

The downside is that although physically stronger, it can be more susceptible to cracking from vibration or impact, especially around welds.  At one time I was close to building an experimental aircraft and the online discussions about welding 4130 tubing were kind of like our oil threads here.

+1

Relevant to our frames, if you use 4130 vs mild steel, and use a thinner wall tube to take advantage of it's higher strength, the frame will flex more.

[Travman]

Any thoughts?  From the 1998 600SS owner's manual.

Ducati claims it is chrome-moly

On the old board there was a similar thread to this current thread.  There were numerous references to chromoly frames in Ducati's literature cited, but the experts all said no.  It was just mild steel when you cut into it.  Plus, Norm just said it was mild steel.  I think Ducati was either trying to make their frames sound more expensive/exotic or they simply made some sort of honest translation mistake. 

[Speeddog]

Well, the alloy that Ducati uses *may* have chrome and molybdenum in it, just not at the levels that would make it 4130.

[Norm]

When I used to fix stock frames, I cut into a lot of them - it ain't chro-mo, it's some kind of mild steel.
If you use a stronger tubing, like chro-mo, you can thin out the walls and then adjust the flex characteristics you want by increasing the diameter. Like everything else, each material has it's own special tricks and you don't learn them all from welding school. When I join a really thin wall to another tube I put an internal sleeve into it. In bicycles, it's referred to as a "double butt". In areas where there is a critical joint, I frequently also add an internal sleeve. As for welding - you don't use chro-mo filler unless you're going to re heat treat the whole thing.
I can go on and on, but if you want to work with a specific material, develop a relationship with one or more experienced welders who have spent years learning, and let them pass on some knowledge.

[ducatiz]

Well, the alloy that Ducati uses *may* have chrome and molybdenum in it, just not at the levels that would make it 4130.

that would be very sneaky and not nice. 

[Speeddog]

that would be very sneaky and not nice. 

Maybe they're trying to pull a fast one, or maybe it's just a translation thing.

[ducatiz]

Maybe they're trying to pull a fast one, or maybe it's just a translation thing.

nah, look at my scan, its in italian first!  then english, spanish, german.. etc..

[MotoCreations]

To add stiffness to a frame -- you have two areas to work with:  wall thickness (weight) or large diameter (thinner wall). (I prefer the latter)

Picture is of an ST2 frame, SportClassic frame and the 1.5in OD 4130 chromoly main tubes I'm using for Orange Kist.  I'll use larger diameter tubes (internally butted) for crossbraces as well.  My goal is to be @6lbs lighter than factory and stiffer torsional/bending resistance (measureable on the factory frame).

note: On some of the bulletin boards is posted the $14K+ titanium frame from NCR.  Beautiful to look at.  But I honestly believe you could build something much better (and lighter) for less money using chromoly and some butted tubing. Too bad someday a frame builder doesn't build a ALS450, 4130 chromoly and a titanium frame to the same specs/geometry -- it really would be interesting to ride all ride and how much the ride/handling would differ between them.

[Raux]

To add stiffness to a frame -- you have two areas to work with:  wall thickness (weight) or large diameter (thinner wall). (I prefer the latter)

Picture is of an ST2 frame, SportClassic frame and the 1.5in OD 4130 chromoly main tubes I'm using for Orange Kist.  I'll use larger diameter tubes (internally butted) for crossbraces as well.  My goal is to be @6lbs lighter than factory and stiffer torsional/bending resistance (measureable on the factory frame).

note: On some of the bulletin boards is posted the $14K+ titanium frame from NCR.  Beautiful to look at.  But I honestly believe you could build something much better (and lighter) for less money using chromoly and some butted tubing. Too bad someday a frame builder doesn't build a ALS450, 4130 chromoly and a titanium frame to the same specs/geometry -- it really would be interesting to ride all ride and how much the ride/handling would differ between them.



Aren't the 696, 1100 and D16 larger tubing with thinner walls

[MotoCreations]

"main tubes" measured in US / OD:

M696/M1100 -- 1.35in
Hypermotard -- 1.125in
Multistrada -- 1.10in
ST2 -- 1.10in
early Supersport / Monster -- 1.00in

I didn't measure the Desmosedichi yet.  No idea on the Streetfighter, S2R800/S4RS/S2R1000 nor 848/1098 superbikes.

note: just sacrificed a MS frame this morning -- damaged due to a frontal hit.  All the welds sheared at the HAZ points as usual.  As typical of most Ducati's, the frame is "soft" and easy to bend.   I can definitely state that 4130 chromoly in the same size tube / wall thickness -- it is MUCH MUCH more difficult to bend than the Ducati factory frame material. 

[ducatiz]

Finally...

http://www.motorcyclistonline.com/howto/answers/122_0907_ask_the_pro/index.html

According to technical types at the home office, the alloy in question is also known as Fe E 420 or E420M UNI 10296-1. ALS is common shorthand for alloy steel, and 450 is the factory's designation for this particularly complicated alloy. More corrosion-resistant than the familiar 4130 chrome moly (a.k.a. chromoly) variety, it's relatively easy to weld and has what engineers like to call "a high modulus of elasticity," making it more durable in a tip-over. ALS 450 debuted in the '95 916's steel-trellis skeleton, and is also employed on the Desmosedici RR, using a different diameter to maintain rigidity without increasing wall thickness. The 15.8-lb. Desmo-sedici RR frame uses four different tubes ranging from 18 to 28mm in diameter, with a wall-thickness of 1.5 to 2mm.

Read more: http://www.motorcyclistonline.com/howto/answers/122_0907_ask_the_pro/index.html#ixzz1Xr7rRikE

[Speeddog]

OK, that's some good info, though I'm a bit skeptical as it's MO, and they say things like this:

"and has what engineers like to call "a high modulus of elasticity," making it more durable in a tip-over."

That's either bad translation, taking bad interview notes, or they're talking to sales and marketing.
No mechanical engineer that knew his ass from a hot rock would say that.



   

[monsta]

ahhm...  dunno about finally!  this is on page 1 of the thread...   

FWIW

From:  http://www.motorcyclistonline.com/howto/answers/122_0907_ask_the_pro/index.html

EN 10296-1
E420M

http://books.google.com/books?id=SpcF9IrYKRoC&pg=PA230&lpg=PA230&dq=e420m+steel&source=bl&ots=CdyBMf50Li&sig=hSjoee_zOWQS_OOANdrpRmNevzM&hl=en&ei=XSaxSsWiLcac8Qb4ybDCDg&sa=X&oi=book_result&ct=result&resnum=4#v=onepage&q=e420m%20steel&f=false

[hillbillypolack]

I have the same literature, and saved articles from mid 90s on Ducati frames.

I seriously doubt the frames are anything close to chrome moly.  For two reasons.  Doing a tail chop on the M900, it was far too easy to cut through, file and work than CrMo.  Also, if it is some mysterious ALS alloy that minimizes rust I'm also not buying it.  Drop the engine from a mid 90s Duc and take a close look at the inner faces which mate to the engine cases.  Rust?  Probably, just as much there as if you snaked a plumbing camera down the frame tube and took a look at it from the inside. 

[ducatiz]

The article I linked said they only introduced the ALS450 on the 95 916, so it probably did not make it to the SS and monsters until later.

I doubt they would baldfacedly lie about it -- and there are so many varieties of chro-moly ...  it's certainly not the same stuff Verlicchi used.